Breakthrough in Coal Mine Remediation: Coal Gangue-Based Geopolymer Aggregate Slurry Shown to be Sustainable and Effective

Strategic Insights -

A team of researchers from Xi'an Research Institute has made a significant breakthrough in the field of coal mine remediation, discovering that coal gangue-based geopolymer aggregate slurry can be an effective and sustainable solution for addressing coal mining subsidence areas and resolving large-scale coal-based solid waste disposal. This innovative approach not only provides a remediation method but also creates a valuable product from waste materials. The research shows that by controlling aggregate particle size and content, the slurry's mechanical properties and transport characteristics can be optimized, making it suitable for use in coal mine goafs.

Key Takeaways:

  • The coal gangue-based geopolymer aggregate slurry, an emerging green material, exhibits excellent stability and suitability for use as backfill in coal mine goafs.
  • The slurry's compressive strength increases with larger aggregate particle sizes, with aggregates sized 20 mm, 10 mm, and 5 mm forming robust load-bearing skeletons.
  • Increasing the aggregate content reduces the slump flow while elevating the yield stress, plastic viscosity, and thixotropy, potentially leading to higher pumping energy consumption and decreased transport efficiency.
  • The research conducted by the Xi'an Research Institute provides theoretical support for engineering applications of gangue-based geopolymer aggregate slurry.
  • The study employed uniaxial compressive strength tests, low-field nuclear magnetic resonance, and scanning electron microscopy to analyze the mechanical properties, pore distribution, and microstructure of the cured slurry.
  • The findings have significant implications for the remediation of coal mining subsidence areas and the disposal of large-scale coal-based solid waste.

Statistics:

  • The compressive strength of the cured material increases with larger aggregate particle sizes, with aggregates sized 20 mm, 10 mm, and 5 mm showing significantly higher strength compared to finer aggregates (0.15 mm and 0.075 mm) (Shuiwen dizhi gongcheng dizhi, 2025,52(4):62-74).
  • The slump flow exhibits an inverse correlation with rheological parameters, with a reduction in slump flow leading to an increase in yield stress, plastic viscosity, and thixotropy (Shuiwen dizhi gongcheng dizhi, 2025,52(4):62-74).
  • The study involved the collaboration of researchers from Xi'an Research Institute and contributed to the development of a sustainable and effective solution for coal mine remediation (NewsRx, 2025).

Sources:

  • Shuiwen dizhi gongcheng dizhi. (2025). Mechanical and transportation characteristics of gangue geopolymer aggregate slurry. Editorial Office of Hydrogeology & Engineering Geology, 52(4), 62-74. https://doi-org.sdpl.idm.oclc.org/10.16030/j.cnki.issn.1000-3665.202502037
  • NewsRx. (2025). Findings from Xi'an Research Institute Advance Knowledge in Business (Mechanical and transportation characteristics of gangue geopolymer aggregate slurry). China Weekly News, August 5, p 218.